Refrigerating machine



May 16, 1933.

P. SCHLUMBOHM REFRIGERATING MACHINE Filed Oct. 20; 1928 2 Sheets-Shep; l

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May 16, 1933.

P. SCHLUMBOHM REFRIGERATINQ MACHINE Filed Oct, 20, 1928 2 Sheets-Sheet.

Patented May 16, 1933 v UNITED STATES PATENT'OFFICE BOTTLE COMPANY, OFNORWICH, CONNECTICUT, ACORPORATION OF OHIO BEII'BIGEBATING MACHINE iApplication filed October 20, 1928, Serial 1T0. 318,748, and in GermanyOctober 21,1927.

My intention relates to refrigerating machines of the type utilizing theevaporation of a liquid to produce low temperature, and its object is toprovide a small compact machine adapted to operate efficiently at lowcost.

According to the present invention, a tank containing a suitable liquidto be evaporated ous cycle.

tank flow down the mercury return pipe to a point where the latterconnects with the tankreturn pipe, through which the condensate returnsto the tank. The level of condensed mercury in the return pipe is belowthe .point where that pipe'connects with the tankreturn pipe, 'so thatthe later is always open to the condensed cooling vapors.

There is thus provided a continuous cycle of evaporation andreturnofcondensed vapors to the refrigerating tank, whereby a substantiallyconstant level of the cooling liquid is maintained. In other words, thecooling medium requires no renewal, and the same is .true of themercury, in the pump, so that the machine, when once started, .needs noattention. To facilitate starting of the mercury vapor pu1np, I connectthe condenser with an aspirator or similar device adapted reduce thevapor pressure in the passage b tween the cooling tank and thecondenser. This as.- pirator or ejector produces a suction pressure ofabout 12 mm. The low pressures at which my refrigerating machineoperates constitute one of the main practical advantages of myinvention, as will be clearfroni a detailed description of theaccompanying drawings in Fig. 1 shows in sectional diagrammatic form apreferred embodiment of my inven- Fig.2 illustrates insection a mercuryseal thait may be used in the apparatus of Fig. 1; an

Fig. 3 is an enlarged section of a preferred form of ejector .oraspirator that may be insorted into the machine shown in Fig. 1.

A'mercury boiler indicated as a whole by 12 contains a quantity ofmercury 22 at the bottom, and is adapted to be heated in anpractical wayto vaporize the mercury.

, PETER BCHLUMBOHI, OF BERLIN, GEBI A NY, ASSIGNOR TO AMERICAN THEBMOBnarrow tube 2 in boiler 12 'is open at the bot- I tom and closed at thetop 3, except for small holes 4 in the side wall. A cone-shapeddeflector or vane 33 projects from the closed top of tube2 into closeproximity to a pipe 13 which surroundsthe upper portion of tube 2. Thecone 33 forms with the adjacent wallof pipe 13 a narrow circular channel5 which forms a nozzle for the passage of air and vapor from a tank 14,with which the pipe 13 is connected. The tank 14 contains a liquid easyto evaporate, and constitutes a refrigerating unit adapted to be placedin a chamber which is to be kept cool. The liquid in tank 14 willusually be water, althoughv other substances withdow vapor pressure mayJ be employed,.'-such as pyridine, octane, and

the like.

The upper portion of themercury vapor pipe 2 is provided with a'jacke34, which is connected at its lower end to t wall of the boiler 12, andthe upper end of the jacket is. attached at 36 to pipe 2 a shortdistance below the holes 33. The pipe 13 terminates at its lower end ina flaring wall 6, which isattach'ed toboiler 12 above the lower end ofjacket 34. The separated flaring members e cylindrical 6 and 34 thusform a space 15 which operates as a condenser and will hereinafter bedesignated as such. The space 2' around pipe 2 maybe evacuated to avoidthe exchange of heat between that pipe and the condenser .15. A returnpipe 19 leads from the bottom of condenser 15 to the bottom of boiler 12for the return of condensed. mercury vapors to the source of supply 22.The lower portion 21 of return pipe 19 preferably extends below themercury supply 22, and this pipe should be of the narrowest possiblecross-section on account of the heat-conductivity of mercury.

A second return pipe 20 leads from the bottom of tank 14 to pipe 19,with which the pipe 20 connects at 7. c

The closed annular space 8 in the upper portion of mercury boiler 12constitutes a water jacket for keeping the condenser 15 cool. Awater-inlet pipe 30 communicates with the lower end of water acket 8,and an outlet pipe 31 leads from the upper end of 1 the jacket. Theinlet pipe 30 forms a water jacket 28, through which the major length ofreturn pipe 19 passes. The cooling liquid enters jacket 2.8 at thebottom through pipe 29 and flows upward through the cooling jackets 28and 8. The outlet pipe 31 connects with the upper end ofan aspirator orejector indicated as a whole by 16, and a narrow pipe 17 connects thisejector with the upper wall of condenser 15. If desired, a cock or valve18 may be includedYin pipe 17 to control the connection betweencondenser 15 and ejector 16. An outlet pipe 32 is connected to the lowerend of the ejector. The purpose.

of ejector 16 is to withdraw air molecules from condenser 15, wherebythe proper degree of vacuum or under-pressure is maintained in pipe 13during the operation of the machine, as will presently be explained.

The above described apparatus operates likethis: As the mercury 22boils.the vapor passes up the pipe 2 and out through the small holes 3 at thetop into condenser 15. suction created by the high-speed downwardpassage of mercury vapor when deflected by vane 33 draws vapor and'airmolecules from tank 14 through the narrow circular nozzle 5, therebyreducing the vapor pressure in tank 14 and lowering the temperature ofthe liquid in the tank. Thus, a mixture of mercury vapor, vapor from theliquid in tank 14, and air molecules that were present in the tank andpipe 13, passes down into the condenser 15. The suction action ofaspiratorlG withdraws the air entrained by the mercury vapor, and thecondensed vapors flow out of condenser 15 through pipe 19. The mercuryportion of this mixture of condensed vapors passes through pipe 19 backto the original supply 22. The condensed vapors thatcame from tank :14are lighter than the mercury vapor and therefore float on top of themercury. As shown in Fig. 1, the mercury level 25 is below theconnection 7 of pipe 20 with pipe 19, so that the column of condensedvapors 9 is open to tank 14 through pipe 20. The level of column 9 isindicated at 23. By extending the lower portion 21 of return pipe 19sufliciently below the level 26 of the mercury in boiler 12,1-he liquidcolumn 9 and the connected column in pipe 20 find a sufiicientcounterweight of mercury to prevent the liquid of those columns fromentering themercury boiler 12. The lower U-shaped portion of return pipe21 always contains mercury,

The

"tor 16 is about twelve millimeters, which also represents the headbetween levels 24 and 25. Before starting the mercury cycle, theaspirator 16 should first be operated to reduce the vapor pressure inpipe 13, so that the mercury vapor pump may properly function. Since thevapors of mercury 22 in boiler 12 and of the evaporating liquid incooling tank 14 are condensed and returned to their respective sources,the levels 26 and 24 remain practically constant and the-machine thusbecomes a complete self-contained refrigerating unit.

Instead of using the manually operated valve 18 in pipe 17 to start andstop the aspirator 16, I may use the automatic arrangement illustratedin Fig. 2. Here the pipe 17 contains a capillary tube 37 about eightycentimeters long, which is connected at its lower end with a closedreceptacle 38 containing mercury 39.' The tube 37 "dips slightly belowthe level of the mcrcuryQwhich fills the receptacle about half. A pipe40, connected to the suction pipe of an ejector 45 (see Fig, 3), alsoextends into receptacle 38 but several centimeters above the mercurylevel. The upper end of pipe 40 is provided with a mercury filter 41,and a similar filter 42 is mounted at the upper end of the capillarytube37. The ejector 45preferably comprises an outer metal tubecontaining a core 43 of glass, porcelain, or similar material,

capable of withstanding the constant flow of cooling water. The core 43is cemented in the metal tube 45 above and below the suction opening 44,the cement being indicated at 49 and 50. Thepipe 40 is connected tosuction pipe 46, and the upper end of core 43 communicates with awater-inlet pipe 47. The lower end of metal tube 45 is open to a water-1 outlet pipe 48.

' Assuming the ejector45 to bein operation, a suction is' created inpipe 40. Should the vacuum in the machine decrease below a predeterminedpoint, and should the pressure in condenser 15 exceed a certain amount,the

mercury seal of suction pipe 40 in receptacle i 65 land before theoperation of the pump the mer- This mercury column prevents the entranceof 9 sure requires a small amount of heat to produce the necessaryquantity of mercury vaair into the machine as long as the ejector.

boiler at about that temperature, so that it now has to be heated from20 C. to the boiling point. The latter depends upon the pressure infront of ejector nozzle 5. By way of example, it may be mentioned thatwith 440 mms. the mercury boils at 328 0.; with 100 mms. at 261 (3.; andwith 50 mms, at 235 C. The pressure existing in condenser 15 correspondsto the saturation pressure of the cooling means at a temperature ofabout 20 C. This saturation pressure is 17 mms. for water and 10 mms.for octane. The saturation pressure of mercury at 20 C. is practicallyzero.

It will be clear from the preceding description that I have provided asmall selfcontained refrigerating machine especially adapted forhousehold use, one that-operates reliably and at a low cost. Since themachine utilizes mercury vapor of low temperature. there is no danger ofdecomposition of the coolingliquid in tank 14. Also, the use of coolingmeanswith low vapor prespor.

Although I have shown and described a specific form of apparatus,changes and mod ifications may be made without departing from the scopeof the invention as defined. in the appended claims.

I claim: V

1. A refrigerating system including a refrigerant pump using mercuryvapor as a propellant fluid. an evaporator connected to the. suction ofthe pump, a condenser receiving the discharge from the pump, and anejector actuated by the condenser water for removing uncondensablc gasesfrom the systom.

2. The structure as defined in claim 1, in which the suction of theejector is connected to the. condenser.

3. The structure as defined in claim 1, in cluding a mercury seal in thesuction conduit of the injector, whereby in the interruption of theinjector the condenser is closed against atmospheric pressure.

4. The structure as defined in claim 1, including a nozzle system inwhich said injector is constructed of a glassdike substance.

5. In combination with a refrigeration system including a water cooledcondenser, an ejector for removing uncondensa-ble gases. from saidsystem, said ejector comprising a metal tube having a water inlet at oneend and a water outlet at the other end, a suction pipe connected tosaid tube near the water inlet, an ejector tube of glass-like materialfixed within said metal tube and forming an airtight joint therewithabove and below said suction pipe, said ejector tube having an inletcommunicating with said suction pipe, and a nozzle forming part of saidejector tube and extending downwardly therein, said nozzle being open tothe Water inlet of said metal tube.

In testimony whereof I aflix my signature.

PETER SCHLUMBOHM.

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